1. Field of the Invention
The present invention relates to a radiographic apparatus, a radiographic table, and a radiographic system which are intended to image radiation, such as X-rays, using a radiation image receiver after it passes through a test subject.
The present invention relates especially to a radiographic apparatus, a radiographic table, and a radiographic system in which radiation, such as X-rays, is projected to a test subject lying on the top of a table, a bed, etc., and the radiation having passed through the test subject is imaged with the radiation image receiver disposed below or beside the top.
2. Related Background Art
Conventional radiographic apparatuses having a radiographic table with a radiographic receiver are used in a variety of fields, such as medical diagnosis and non-destructive inspection. These apparatuses use so-called radiography, which uses sensitizing paper and radiographic film brought into close contact with each other. When radiation is incident on sensitizing paper in such a radiographic apparatus after passing through a test subject, phosphors contained in the sensitizing paper absorb radiation energy and fluoresce. Then radiographic film is exposed to fluorescence, so that a radiation image is recorded on the film. And visible radiation image is obtained by developing the film.
An image recording/reproducing apparatus was recently invented which has a radiation detector including photostimulable phosphors. When radiation passes through a subject and is incident on photostimulable phosphors, constituting the radiation detector, the phosphors accumulate part of the radiation energy received. When the photostimulable phosphors are exposed to light, for example, visible light, they exhibit an accelerated phosphorescence emission according to the amount of radiation energy accumulated. That is, the photostimulable phosphors collect information on an radiation image of the subject; scanning means scans the photostimulable phosphors, using excitation light, such as laser beams; signal reading means reads the light of the accelerated phosphorescence emission photoelectrically; and recording material, such as photosensitive material, or displaying means, such as a CRT, records or displays read image information as a visible image.
Because of advanced semiconductor processing technology, digital radiation image detectors have been proposed which directly supply digital radiation image data on a real-time basis. Such a digital radiation image detector is disclosed in, for example, Japanese Patent Application Laid-Open No. 8-116044. The digital radiation image detector comprises a scintillator and a solid-state light detector, which are placed one on top of the other. The scintillator converts radiation into visible light, and the solid-state light detector converts visible light into electricity. The solid-state light detector can be produced by disposing on a substrate made of silica glass a matrix of solid-state light detecting elements which consist of an amorphous semiconductor film and conductive films which sandwich the semiconductor film. One of the conductive films is transparent.
Because a digital radiation image detector of this type is flat and a few millimeters thick, using such a detector for a radiation image receiver helps reduce the thickness and weight. Moreover, a radiation image receiver containing such a digital radiation image detector directly provides a digital image without using consumables, such as a film and a photostimulable phosphor sheet. Thus, the radiation image receiver is free from repeated operations which conventional radiation image detectors need, such as loading a cassette containing a film or a photostimulable phosphor sheet at a predetermined position, unloading the cassette after imaging and developing or processing the film or the photostimulable phosphor sheet. This, in turn, means that the radiographer is released from troublesome operations.
It is an object of the present invention to provide a radiographic apparatus, a radiographic table with a radiation image receiver, and a radiographic system which allow the radiographic region covered by the radiation image receiver (the position or the posture of the radiation image receiver) to be properly adjusted according to a test subject, a method for radiographing a test subject (i.e., the direction in which a test subject is exposed to radiation and the posture of the subject), etc.
It is another object of the present invention to propose a radiographic apparatus and a radiographic system which allow the position of a radiation source to be properly adjusted according to a test subject, a method for radiographing a test subject (i.e., the direction in which a test subject is exposed to radiation and the posture of the subject), etc.
Other objects of the present invention will become clear from the following description of embodiments.